Then I saw “a new heaven and a new earth,”[a] for the first heaven and the first earth had passed away, and there was no longer any sea. 2 I saw the Holy City, the new Jerusalem, coming down out of heaven from God, prepared as a bride beautifully dressed for her husband. 3 And I heard a loud voice from the throne saying, “Look! God’s dwelling place is now among the people, and he will dwell with them. They will be his people, and God himself will be with them and be their God. 4 ‘He will wipe every tear from their eyes. There will be no more death’[b] or mourning or crying or pain, for the old order of things has passed away.”
5 He who was seated on the throne said, “I am making everything new!” Then he said, “Write this down, for these words are trustworthy and true.” - Revelation 21:1-5
Christians, like myself, believe that after the Earth is destroyed, God will create a new and perfect one. That's what comes after Heaven.